<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1">
  <meta charset="utf-8">
  <meta name="theme-color" content="#222222">
  <title>WLED 模拟预览</title>
  <style>
  body {
    margin: 0;
  }
  #canv {
    background: black;
    filter: brightness(175%);
    width: 100%;
    height: 100%;
    position: absolute;
  }
  </style>
  <script>
    var ws;
    var tmout = null;
    function update() // via HTTP (/json/live)
    {
      if (document.hidden) {
        clearTimeout(tmout);
        tmout = setTimeout(update, 250);
        return;
      }
      fetch('./json/live')
      .then(res => {
        if (!res.ok) {
          clearTimeout(tmout);
          tmout = setTimeout(update, 2500);
        }
        return res.json();
      })
      .then(json => {
        var str = "linear-gradient(90deg,";
        var len = json.leds.length;
        for (i = 0; i < len; i++) {
          var leddata = json.leds[i];
          if (leddata.length > 6) leddata = leddata.substring(2);
          str += "#" + leddata;
          if (i < len -1) str += ","
        }
        str += ")";
        document.getElementById("canv").style.background = str;
        clearTimeout(tmout);
        tmout = setTimeout(update, 40);
      })
      .catch(function (error) {
        clearTimeout(tmout);
        tmout = setTimeout(update, 2500);
      })
    }
    function S() { // Startup function (onload)
      let wsOn = (window.location.href.indexOf("?ws") > 0);
      if (!wsOn) {update(); return;}

      // Initialize WebSocket connection
      try {
        ws = top.window.ws;
      } catch (e) {}
      if (ws && ws.readyState === WebSocket.OPEN) {
        //console.info("Peek uses top WS");
        ws.send("{'lv':true}");
      } else {
        //console.info("Peek WS opening");
        let l = window.location;
        let pathn = l.pathname;
        let paths = pathn.slice(1,pathn.endsWith('/')?-1:undefined).split("/");
        let url = l.origin.replace("http","ws");
        if (paths.length > 1) {
          url +=  "/" + paths[0];
        }
        ws = new WebSocket(url+"/ws");
        ws.onopen = function () {
          //console.info("Peek WS open");
          ws.send("{'lv':true}");
        }
      }
      ws.binaryType = "arraybuffer";
      ws.addEventListener('message', (e) => {
        try {
          if (toString.call(e.data) === '[object ArrayBuffer]') {
            let leds = new Uint8Array(event.data);
            if (leds[0] != 76) return; //'L'
            let str = "linear-gradient(90deg,";
            let len = leds.length;
            let start = leds[1]==2 ? 4 : 2; // 1 = 1D, 2 = 1D/2D (leds[2]=w, leds[3]=h)
            for (i = start; i < len; i+=3) {
              str += `rgb(${leds[i]},${leds[i+1]},${leds[i+2]})`;
              if (i < len -3) str += ","
            }
            str += ")";
            document.getElementById("canv").style.background = str;
          }
        } catch (err) {
          console.error("Peek WS error:",err);
        } 
      });
    }
  </script>
</head>
<body onload="S()">
  <div id="canv"></div>
</body>
</html>